1. Field of the Invention
This invention-relates to an image processing apparatus and method for regulating the total quantity of a developer used during image formation.
2. Related Background Art
As a color image recording system, a system is known comprising a host apparatus for transferring recording data, and a color ink jet recording apparatus for receiving the recording data from the host apparatus and causing a plurality of colors of inks to adhere to a recording surface in accordance with the data to thereby accomplish recording.
In this system, in the host apparatus, image data are represented by three primary colors, R. G and B to carry out processing and for display by a display device and on the other hand, in the recording apparatus, it is usual that image data represented by four colors, C, M, Y and K to effect recording by inks of four colors, C, M, Y and K.
In such a system, the correction/conversion processing from an RGB value depending on the display device to a CMYK value depending on the recording apparatus must be carried out. At this time, data corresponding to one page to be printed by the recording apparatus may be prepared, whereafter the above-described conversion processing may be carried out on all pixels, but recently, there is a system adopting a method of subjecting an object placed on a page, for example, graphics such as a line or a circle, or an image such as characters and a scanning image, to the above-described conversion in advance when data corresponding to one page are prepared, and placing it on the page, in order to increase the processing speed.
However, in a system adopting such method, it is originally supposed that the display device is used and therefore, it is possible to place the object on the page in three colors, R, G and B, but it is often impossible to correctly convert it to four colors, C, M, Y and K used in the recording apparatus.
In such a system, the correction/conversion processing from RGB to CMYK adopts the procedure of correcting the RGB value depending on the display device which is a color attribute individual objects have into RGB depending on the recording apparatus, using this value to dispose the object on the page, preparing data corresponding to one page, and thereafter making the RGB value depending on the recording apparatus into a CMYK value depending on the recording apparatus for all pixels. Here, the processing carried out on individual objects is called the color correction processing, and the processing for all pixels corresponding to one page is called the color conversion processing. This color conversion processing converts the RGB value depending on the recording apparatus into a CMY value, and further into a CMYK value.
In this color conversion processing, it is usual that one of three colors, C, M and Y which has the smallest value is replaced with K as a non-coloring, component (black generation processing), and K is subtracted from the values of the original data, respectively (under color removal processing), whereby the data are converted into data corresponding to four colors, C, M, Y and K.
The data subjected to the correction/conversion processing from RGB into CMYK in this manner are finally subjected to the output gradation correction processing for correcting the data input value vs. output density characteristic of the recording apparatus into a linear form.
Generally, in an image forming apparatus, when the smallest value of three colors, C, M and Y, is replaced with K by black generation and under color removal processing, the level for properly forming an image in the image forming apparatus is sometimes exceeded, and this has led to the problem that the quality of an output image deteriorates.
The latest recording apparatuses include ones in which it is possible to make the resolution of the recording apparatus variable by setting means for setting the resolution. In such recording apparatuses, when high resolution is set, this problem remarkably appears and the quantity of recording material per unit area exceeds a predetermined quantity, and this has led to the problem that the quality of an output image is deteriorated.
The present invention has been made in view of the above-noted points and an object thereof is to control a total output level to thereby prevent it from exceeding a level at which an image can be properly formed by an image forming apparatus.
Another object of the present invention is to provide an image processing apparatus comprising input means for inputting color image data, and color correction means for effecting under color removal processing and black generation processing conforming to the characteristic of a recording medium on said color image data, and outputting data indicative of a plurality of color components including a black component, characterized in that said color correction means effects said under color removal processing-and said black generation processing so that the total output level of said data indicative of the plurality of color components including said black component may assume a value conforming to said color image data.
The present invention has been made in view of the above-noted points and an object thereof is to control gradation correction processing so that an output image may be properly formed in conformity with set resolution.
Another object of the present invention is to provide an image processing apparatus for outputting image data to an image forming apparatus capable of forming an image on a recording medium by using a recording material at a plurality of resolutions, characterized by:
setting means for setting resolutions, gradation correction processing means for performing gradation correction processing; and
control means for controlling the gradation correction processing of said gradation correction processing means to regulate the total quantity of said recording material in conformity with said set resolution.
Many widely different embodiments of the present invention may be constructed without departing from the spirit and scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments described in the specification, except as defined in the appended claims.